Water resistant welt shoe construction



April 10, 1962 BAlLEY 3,028,690

WATER RESISTANT WELT SHOE CONSTRUCTION Filed April 14, 1959 5" I I I I lrurillll INVENTOI/L /1// 704 34/45 United States Patent 9 3,028,690 WATER RESISTANT WELT SHOE CONSTRUCTION Milton Bailey, New York, NY. (36 Kenilworth Place, Brooklyn 10, N.Y.) Filed Apr. 14, 1959, Ser. No. 806,410 5 Claims. (Cl. 36-17) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to improvements in welt shoe construction, and more particularly pertains to improvements in water-resistant Welt shoe seam sealing construction.

Decks inundated with water continually pose a hazard to' health, safety and well-being of naval personnel. Conventional footgear designed primarily for use on land,

fails to afford the required protection when subjected to the corrosive elements of the sea. Inadequate shoes engender ills and discomforts associated with wet feet. The continuous wetting and drying of the shoes accelerate the deterioration process, requiring large stocks and issues to support the fleet. The subject water-resistant shoe resolves these major shipboard problems. The shoe incorporates a combination of advanced components, including water-resistant leather, non-marking heels and soles, and polyethylene counters; also shoe seams are so sealed as to bar the penetration of water through the stitch holes.

In one waterproof double vamp construction, the upper and lower vamps are sewed, the lower vamp lasted and its edges cemented to a flat innersole, a self-curing rubber sheet laid over the flat innersole, a lipped innersole cemented to the cured rubber surface, and the upper vamp lasted. Inseaming of plastic welt around the bottom of the shoe, adding the shank piece, filling the cavity with a thermoplastic cork mixture, and then attaching a rubber sole and heel completes the construction. However, this method of fabrication requires careful handling and the use of additional materials, which slow down production and increase the cost of the shoe. Additionally, the method provides a shoe that is still, heavy and limited to hard duty work use.

In an alternate double vamp construction, the inside vamp is joined to the welt and insole by the conventional welt inseam technique, and the outside vamp is attached by the stitcho'own method, by a lockstitch, through the rubber midsole and rubber outsole. Although more resistant to water penetration than conventional welt conructions, this method does not provide the function required-leather shoes made according to this method permit water to penetrate through the inseam and upper areas.

The problem of providing adequate resistance to the penetration of water during walking, running, or subjecting a shoe to other dynamic tensions, is solved by the subject invention, which provides a shoe construction that includes seam sealed stitches, wherein the joined parts in the Welt and the upper areas of the shoe, when water resistant upper leathers are employed, are essentially impervious to water. (Such upper leathers may be Bavon-treatedsoaked or coated with an alkenyl succinic acid solution.) The result, quantitatively, is a shoe adapted to resist water penetration over a period of months wear in environments such as aboard ships and extremely wet land facilities.

The principal object of this invention is to provide an improved water resistant welt shoe construction and seam sealing means.

Other objects and many of the attendant advantages ice of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein FIG. 1 is a side elevation of a shoe with parts broken away, showing a preferred embodiment of the invention; and

FIG. 2 is an enlargement of a section taken on the line 22 of FIG. 1.'

Similar numerals refer to similar parts throughout the several views.

The first series of steps in constructing the waterproof shoe comprises upper seam sealing. In such steps, the skived edges 13 of the vamp 15 and quarters 17 are daubed with a viscous elastomeric adhesive, such as Du Pont Clear Windshield Sealer No. 5491 (a clear colorless adhesive composed of a plasticized polyvinyl butyral base and a non-bleeding phthalate plasticizer, the gallon weight being not less than 7.40 pounds with a minimum total solids content of 19 percent and a viscosity of 40 to 50 seconds using a No. 25 Parlin Cup ASTM Method D553-42) or Minnesota Mineral and Mining Company adhesive EC776 (a Buna-N base adhesive as defined in the specification MIL-S4383). The quarter edges are then connected and pressed to the corresponding vamp edges and the seams 19 double stitched immediately, using suitable commercial threads such as cotton or nylon, and the upper stitching inside the shoe is coated with a ribbon of seam sealer 21. The outside upper stitching 23 is then brushed with a concentrated alkenyl succinic acid solution or a 20% silicone solution (as described in US. Letters Patent Reissue No. 23,879).

The box toe Z5 and polyethylene counter 27 are then I incorporated, and the shoe lasted by conventional means.

In the lasting process, the uppers are pulled over and the front and sides are secured with welt tacks. The sides are then lasted and fastened with staples, and the heel parts are pulled in and secured with brass tacks. After the toes are wiped in and secured with a wire, the side tacks are pulled and the toes trimmed.

Upon completion of the above lasting operations, the inseam and welt seam sealing is accomplished. The entire bottom punctured edge 29 of the shoe is inundated with a viscous elastomeric adhesive sealer 31 such as Du Pont Clear Windshield Sealer #5491, or Minnesota Mineral and Mining Company EC776, or a self-vulcanizing rubber. A plastic vinyl welt 33, such as a polyvinyl co-polym-er capable of three or four 180 flexes at --30 F. without cracking, having a Shore Durometer hardness of to 90, so that it is adapted to seal the needle punctures and flow about the Goodyear stitching threads, is then sewn to the upper and insole 35 with a hygroscopic linen inseam thread 37. As the needle passes through the connecting parts, the inseam thread absorbs and carries the viscous sealer through the stitch holes forming a hydrophobic seam. The sealer cures at room temperature, plugs the holes, and forms a resilient elastomer that remains intact as the inseam flexes during Walking.

The insole tacks are then pulled and the insole edges trimmed. The welting, trimmed inseam, heel seat and insole areas are then given a heavy coat of sealer 39 and allowed to cure, after which a cork filler 41 and shank 43 are laid on the shoe bottom. Rubber non-marking soles 45 attached to a plastic or rubber midsole 47 are cemented to the bottom and Goodyear stitched by stitches 49 (lockstitch seaming) to the plastic Welt, which has been treated with the seam sealer. The Goodyear threads can be cotton, linen or a synthetic material.

The heel seat is fastened with fiber pegs. A wood core heel 51 (without washers) is attached. Finally, sole. stitching is treated with silicone or alkenyl succinic acid solution and a coat of colorless seam sealer is ap plied over the welting, including the upper Where it is adjacent to or joins the welting.

It is thus evident that the fabrication sequence described above follows conventional means of manufacturing welt footwear but departs sufficiently from such means to achieve Waterproofness. The technique described takes advantage of the tacky, cold-flow and adhesive properties of thermoplastic and elastomeric materials that are applied strategically to the inseam and upper seam areas of the shoe. The weight and flexibility of the shoe are not affected materially by such techniques, as a solvent type, self-curing elastomer is employed, in lieu of latex and softer curing thermoplastic materials that tend to creep and flow readily, and thus fail to caulk the holes and prevent formation of channels through which water can enter the shoe.

Seam-seal methods heretofore used did not apply the adhesive stitch plug principle. The tacking resilient seam sealers of this invention are pushed in by the inseam needle and adhere to the inseam cord, thus forming a coated elastic plug-the sealer, while still tacky, viscous and uncured, flows into the punctured needle and nail holes.

When the soft rubber, wood based full heel is attached, the nails sink below the rubber and are covered by the surface rubber that spreads over the nails, so that water penetration is blocked and the nails are protected from corrosion for the life of the shoe. The protective elastomeric outside welt coating assures additional protection against water leakage: The sealer blends readily with the leather and plastic in the welt area and forms a continuous protective film without detracting from the appearance of the footwear.

An alternate method of fabrication comprises precoating the inseam thread and upper with an appropriate seam sealer. As the stitching threads are drawn through the elastomer it is cured partially by heat and then reactivated by appropriate solvent or activator just prior to stitching. Upon completion of the stitching, additional sealer can be brushed into and on the punctured shoe areas. Finally, the exposed, cured threads and leather can be daubed or sprayed with a silicone or with an alkenyl succinic acid solution.

In another alternate method, the inseam and upper threads are precoated with seam seal elastomer just prior to the stitching, followed by the brushing of sealer on the appropriate punctured areas, and finally spraying or daubing of the cured or exposed threads and leather with either silicone or alkenyl succinic acid solutions.

The addition of methylene bis-t(4-phenyl isocyanate) in O-dichlorobenzene increases the bonding power of the sealers.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. For example, the method described can be applied to other sewn shoes, including the McKay Welt, the Stitchdown, the Nailed Work and the Pre-Welt shoe. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. in a shoe having a midsole, a vamp and a welt member, the improvement comprising a layer of a waterproof adhesive sealing composition positioned between and bonding together juxtaposed portions of said welt member, said vamp and said midsole, and hydrophobic stitches extending through said adhesive sealing composition and securing said welt to said vamp and said midsole.

2. The combination of claim 1 in which said sealing composition is a viscous elastomeric adhesive.

3. The combination of claim 1 wherein said improvement further includes a quantity of adhesive sealing composition between, and bonding together, said stitches and the portions of said welt, vamp and midsole through which the stitches extend.

4. The combination of claim 3 in which said sealing composition is a plasticized polyvinyl butyral base and non bleeding phthalate plasticizer.

5. The combination of claim 3 in which said sealing composition is a buna-N base adhesive.

References Cited in the file of this patent UNITED STATES PATENTS 2,028,054 Flint Jan. 14, 1936 2,329,290 OGorman Sept. 14, 1943 2,371,204 Wright Mar. 13, 1945 2,390,485 Wright Dec. 4, 1945 2,480,689 tAllen Aug. 30, 1949 2,817,163 Clark Dec. 24, 1957 

1. IN A SHOE HAVING A MIDSOLE, A VAMP AND A WELT MEMBR, THE IMPROVEMENT COMPRISING A LAYER OF A WATERPROOF ADHESIVE SEALING COMPOSITION POSITINED BETWEEN AND BONDING TOGETHER JUXTAPOSED PORTIONS OF SAID WELT MEMBER, SAID VAMP AND SAID MIDSOLE, AND HYDROPHOBIC STITCHES EXTENDING THROUGH SAID ADHESIVE SEALING COM- 